Week 10 (FYP 2)

              By this week, I try to create my flow chart of software  program. The figure below shows the flow chart of Electronic Stethoscope and the flow chart below was explained about the how program of Arduino function and how it's calculated to count the heart beat per minute. The programming not count for one minute to shows the result, but it's just calculate average for 30 second of heart beat detected by diaphragm.

Figure 1: Flow Chart of Electronic Stethoscope

This is a flow chart for this project that is Electronic Stethoscope. First of all, when the button start is pull on, the pre-scan for vibrating normal heart beats will count until 3 second. Then this programming of Arduino will divide the instruction to run 2 programs at the same time that is for the time setting 30 second and then for heart beats that is counting in the time of 30 second. Then this program with mathematical calculation will multiple with 2 for the result of heart beats per 30 second to get the output result total that is in beats per minute, then display it at LCD monitor.

Week 9 (FYP 2)

                 In this week, I try to construct circuit at PCB layout using Altium Designer Release 10- Beta software.  Altium Designer is an EDA software package for printed circuit board, FPGA and embedded Software design, and associated library and release management automation. It is developed and marketed by Altium Limited of Australia. This software is very friendly user because it's can automatic in design of circuit. It's didn't need to manually to draw the circuit to line by line as usual.

Figure 1: PCB layout of Op-Amp circuit

Figure 2: PCB layout of Arduino circuit

Week 8 (FYP 2)

                 For this Week, I try to construct the circuit of the amplifier to connect to the Arduino circuit and view the result using the oscilloscope. When I test the circuit using Op-Amp OPA 344 I get the result what I want but it's have some noise on the waveform of output result. The figure below show the output waveform get from the amplify signal from the Op-Amp OPA 344. The final circuit is the best circuit when the gain is higher enough to increasing the input signal to the output at the end of the circuit.

Figure 1: Testing circuit viewing on Oscilloscope 

                 The output waveform display on output waveform below shows the signal was amplify by the operational amplifier (OPA 334) received heart beat sound from the microphone or when output equal to '1'. The point (A) shows the signal when sensor detected the sound of heart beat and point (B) shows the no sound detected by the sensor or when output equal to '0'  but it have a some noise from the surrounding because of it have a little bit waveform from there. Then, the second figure below shows the waveform when output is received the LED on the circuit also become to turn ON.

Figure 2 : Output waveform

Figure 3: Digital Output (LED turn on)

              

                     

Week 7 (FYP 2)

                 

             By this week, I try research and to find the data sheet of Operational Amplifier OPA 344. These Op-Amp functioning as to amplify the sounds of voice or as Audio processing. the description of Op-Amp  OPA 334 is to series rail-to-rail CMOS operational amplifiers are designed for precision, low-power, miniature applications. The OPA 344 is unity gain stable, while the OPA 345 is optimized for gains greater than or equal to five, and has a gain-bandwidth product of 3MHz. The OPA 344 is optimized to operate on a single supply from 2.5V and up to 5.5V with an input common-mode voltage range that extends 300mV beyond the supplies. Quiescent current is only 250μA (max).

Figure 1: Operational Amplifier OPA 344, 345

                Rail-to-rail input and output make them ideal for driving sampling analogue-to-digital converters. They are also well suited for general purpose and audio applications and providing I /V conversion at the output of D /A converters. Single, dual and quad versions have identical specs for design flexibility. OPA 344 series op amps are unity gain stable and can operate on a single supply, making them highly versatile and easy to use. The op-amp was to amplify the sounds of voice, door knocks and so on. Other then that, the application of the op-Amp is to processing audio.

Week 6 (FYP 2)

           

                 For this week, I try to test my circuit use my old block diagram by using Op-Amp (Non-inverting), Voltage comparator (Switching  circuit) to amplify the output but it's failure because of many noise ad distortion on signal of the waveform when test using Oscilloscope. Then, I do my research to find the suitable Op-Amp to amplify the signal of sound. lastly, I found one useful webpage for my research that use Electret Microphone with Op-Amp OPA 334.  

Website: http://microcontrollershop.com/product_info.php?products_id=4535 

The website also include the schematic diagram shows as below:

Figure 1: Electret Microphone Board Schematic

               When I test the schematic circuit above it's most functioning with smooth output and I decide to use these Op-Amp OPA 334 as a amplifier compared to use the old method. The figure below shows the my new block diagram and new schematic diagram :

Figure 2: Block Diagram of Electronic Stethoscope

Figure 3 Schematic Diagram of Electronic Stethoscope

                The schematic diagram above explain detail about the block diagram and what the components use for this project and also how the flow process the project functioning. Firstly, condenser sensor receives the signal from the attached microphone stethoscope to the chest and then submitted to the operational amplifier (OPA334). After that, the Op-amp amplify the signal from the sensor before transfer data for create the program using Arduino software. Lastly, the reading of heart beat was display at the LCD.